What is the recommended emergency department workup for a 33-year-old female presenting with leg pain and swelling concerning for Deep Vein Thrombosis (DVT)?

Emergency Department Workup for Suspected DVT in a 33-Year-Old Female

The recommended emergency department workup for a 33-year-old female presenting with leg pain and swelling concerning for DVT should begin with compression ultrasound (CUS) of the proximal deep veins as the initial diagnostic test. 1

Initial Assessment

• Evaluate clinical presentation including unilateral leg swelling, pain, erythema, and dilated veins which are common symptoms and signs of DVT 2
• Position the patient with the lower extremities in a dependent position (reverse Trendelenburg or semi-sitting with 30 degrees of hip flexion) to facilitate vein distension for optimal ultrasound examination 1
• Consider risk factors for DVT including recent immobilization, surgery, pregnancy, cancer, or history of previous DVT 1

Diagnostic Testing Algorithm

First-Line Imaging

• Proximal compression ultrasound (CUS) should be performed as the initial test, focusing on the common femoral and popliteal veins 1
  • Use a linear array vascular probe with frequency of 6-10 MHz and width of 6-8 cm 1
  • Evaluate for compressibility of the veins - inability to compress the vein completely indicates presence of thrombus 1

Interpretation and Follow-up Testing

• If proximal CUS is positive (non-compressible vein segment):

  • Treat for DVT without need for confirmatory venography 1

• If proximal CUS is negative:

  • Perform D-dimer testing (preferably a highly sensitive assay) 1
  • If D-dimer is negative: No further testing is needed 1
  • If D-dimer is positive: Schedule repeat proximal CUS in 1 week 1

Alternative or Additional Testing

• Consider whole-leg ultrasound instead of proximal CUS if:

  • Patient is unable to return for serial testing 1
  • Patient has severe symptoms consistent with calf DVT 1
  • If whole-leg US is negative, no further testing is needed 1

• For patients with extensive unexplained leg swelling with negative proximal or whole-leg US:

  • Image the iliac veins to exclude isolated iliac DVT 1
  • Consider Doppler US of iliac veins, CT venography, or MR venography 1

• When ultrasound is impractical or nondiagnostic (e.g., excessive subcutaneous tissue, leg casting):

  • Consider CT venography, MR venography, or MR direct thrombus imaging 1

Important Considerations and Pitfalls

• A negative scan for lower extremity DVT does not rule out pulmonary embolism 1
• Be aware that the superficial femoral vein is actually part of the deep venous system despite its confusing name 1
• Consider the possibility of iliac or inferior vena cava obstruction as a cause for leg pain or swelling 1
• Physical examination alone is only about 30% accurate for DVT diagnosis and cannot be used to exclude DVT 3
• Patients with suspected isolated calf or distal DVT require repeat venous evaluation if not treated with anticoagulation 1
• For pregnant patients with suspected DVT, the initial evaluation should be with proximal CUS, followed by either serial CUS (day 3 and day 7) or D-dimer testing if the initial CUS is negative 1

By following this evidence-based approach, emergency physicians can accurately diagnose DVT and initiate appropriate treatment to prevent complications such as pulmonary embolism and post-thrombotic syndrome.